Quoting: JuliusDoes anyone know if the Selaco devs will switch over and where they plan to upstream their engine improvements now? I haven't followed this very closely.

A couple Selaco devs have talked about this in their Steam forums, thankfully. They currently use a very modified version of GZDoom that they maintain themselves, so they weren't really effect by this whole situation at all. Their custom engine version is completely public and open-source, but I imagine it isn't good for general use due to how Selaco-fied it is. I think they pull from GZDoom(or now UZDoom, in reality) and add to it whenever they deem it would be beneficial for whichever direction the changes go. But I don't think they'll rebase the Selaco engine to UZDoom, at least not anytime soon since by the time that they would think it's a good idea to do so, UZDoom will likely have already made a ton of changes that would break lots of stuff in Selaco. Not a dev though, so just a theory on my part.